Pressure roller apparatus for rock breaking

ABSTRACT

This invention relates to methods of rock breaking which comprise orbiting small rollers around a backing roller that is urged towards the rock face. The rollers each have a raised working zone which is preferably circular in section and which may have hard metal inserts. The rollers may be moved in an arc over the rock face or may be moved stepwise thereof. The working zones apply substantial localized forces to the rock face which forces cause the rock face to break.

O United States Patent [151 3,645,579

Marcovitch Feb. 29, 1972 [54] PRESSURE ROLLER APPARATUS FOR 2,894,727 7/1969 Henderson ..175/338 X ROCK BREAKING 1,276,686 8/1918 Petermann...

1,404,835 1/1922 [72] Inventor: Jacob Marcovitch, Johannesburg, Republic 2,024,764 12/1935 of South Africa 2,184,068 12/1939 2,606,012 8/1952 [73] Assignee. 323w Profile Anstalt, Vaduz, Liechten 2,664,281 12,1953 3,041,055 6/1962 [22] Filed: July 10, 1969 Primary Examiner-Ernest R. Purser [2]] Appl' 0:135 Attorney-Young8zThompson [30] Foreign Application Priority Data ABSTRACT Aug .2, 1968 South Africa ..68/4996 Thi invention relates to me hods of rock breaking which comprise orbiting small rollers around a backing roller that is [52] U.S.C1 ..299/75, 175/338, 229/10, urged towards the rock face. The rollers each have a raised 299/86 working zone which is preferably circular in section and which [51] Int. Cl. ..E21c 37/04 may have hard metal inserts. The rollers may be moved in an [58] Field of Search ..299/ 10, 18, 75, 40, 86; arc over the rock face or may be moved stepwise thereof. The 172/777, 778; 175/338, 319, 354 working zones apply substantial localized forces to the rock face which forces cause the rock face to break.

56 R f C'ted l e erences 11 Claims, 19 Drawing Figures UNITED STATES PATENTS 9 B 1 99.-z-;:;-:.::.;;;-;.:-11:11:31;'zwnljfli i a W me td Feb. 29, 1972 3,645,579

8 Sheets-Sheet 2 89%m *dM Pateb ed Feb. 29, 1972 I 3,645,579

8 Sheets-Sheet 3 P genigd Feb. 29, 1972 3,645,579

8 Sheets-Sheet 4 Patented Feb. 29 1972 I s Sheets -Sheet e Patenied Feb. 29, 1912 3,645,579

8 Sheets-Sheet 8 Away PRESSURE ROLLER APPARATUS FOR ROCK BREAKING This invention relates to rock breaking, particularly in underground mining.

Several forms of rock-breaking machines and systems are known. Among them are percussion drilling (generally as a preliminary to breaking out rock with explosives), diamond drilling, cutting, jet piercing and even such sophisticated techniques as cutting by the use of laser beams.

In underground mining in South Africa, considerable thought has been given recently to rock cutting as an alternative to traditional techniques. At least one cutting machine has been developed and tested, relying on the use of a sharp-edged cutting head or blade mounted on a reciprocating ram to cut a groove in the rock face. Although further development of this principle may lead to a machine suitable for use on a large scale, rock cutting has certain inherent disadvantages which are accentuated under local production conditions. One of these is the comparatively large force which must be exerted to keep the cutting head properly in action. Another is the fact that, at some depth, there is considerable pressure on the rock, and the groove tends to narrow behind the cutting head.

It has also been proposed to break rock by traversing its surface with an instrument called a roller bit, which in basic construction is somewhat like a spur gear. As the individual teeth pass and make contact with the rock, they exert a localized pressure which tends to cause the rock to chip. However, this machine has not been put to wide use, and the heavy wear on the teeth is thought to be one of the drawbacks which has held it back. 7

The object of the invention is to provide a novel rock-breaking system which avoids or lessens the disadvantages of the known systems.

According to one aspect of the invention there is provided a method of breaking rock comprising traversing the surface of the rock with a series of small rollers that are moved in an endless orbital path around backing structure on which the ends of the rollers roll, the rollers having a raised central rockworking zone which impinges on the rock surface, force being applied to the backing structure to cause the rollers to apply substantial localized pressure to the rock as they impinge on it.

The momentum of each roller in its orbital path gives it a quasi-percussive effect as it strikes the rock, and at the same time the force applied continuously to the backing structure ensures penetration of the working zone of the roller into the rock body. Because of its friability, the rock chips or crumbles under the action of the rollers; and the more friable the rock, the more effective the method will usually be.

According to another aspect of the invention their is provided a machine to carry out the above method comprising a series of small rollers mounted for movement in an endless orbitalpath around backing structure on which the ends of the rollers are supported, each roller having a raised preferably circular section, central rock-working zone, means to drive the rollers in their path relatively to the backing structure, and means to apply force to the backing structure so that the working zone of the rollers may impinge with substantial localized pressure on the rock surface and cause it to break.

In a preferred form, the backing structure is a large roller in which the ends of the small rollers roll in line contact. The small rollers are retained in a cage or the like, and the backing roller and cage are driven to move the small rollers in their path.

Supporting means will usually be provided to hold the machine stably to allow it to operate on the rock surface. In underground mining, the supporting means may take the form of props or the like.

Several embodiments of the invention are described below with reference to the accompanying drawings, in which:

FIG. I is a fragmentary plan view of a rock-breaking machine operating on a rock face;

FIG. 2 is a semidiagrammatic view indicating the pattern of movement of the machine of FIG. 1 relatively to the face;

FIGS. 3 and 4 are plan views of a single small work roller operating on a rock face, illustrating the manner in which the rock is broken;

FIG. 5 is a side view of a rock-breaking unit having a circular backing roller on which the ends of a series of work rollers are supported;

FIG. 6 is sectional view through the machine of FIG. 5;

FIG. 7 is a plan view of a rock-breaking machine showing means for applying force to its backing structure;

FIG. 8 is a plan view ofa stope layout in which a machine of the invention is installed;

FIG. 9 is a view in elevation of the arrangement of FIG. 7;

FIG. 10 is a plan view partly in section of another machine designed for operating in a stope or similar excavation;

FIG. 11 and 12 are detail sections of the machine of FIG. 10;

FIG. 13 is a plan view showing the action of the roller of the rock-breaking head of the machine of FIG. 10;

FIG. 14 shows in plan a modified form of machine;

FIG. 15 shows detail from the machine of FIG. 14;

FIG. 16 shows in elevation a modified version of the machine of FIGS. 14 and 15 operating in a working place;

FIG. 17 shows an arrangement for moving the head in an arcuate path; and

FIGS. 18 and 19 show views from different directions of yet another form of machine.

FIGS 1 and 2:

Referring now to FIG. I, a rock face 10 such as that of a stope is being gradually advanced under the action of a series of small work rollers 12 that move in an orbital path around the circumference of backing structure in the form of a large backing roller 14. Each roller 12 has a raised, central circular section, working zone 16 that is accommodated in a groove 18 in the backing roller I4, with the ends 17 of the rollers 12 in rolling line contact with the body of the roller 14. The rollers 12 are held in a cage 20 that surrounds the roller 14 and moves with the small rollers 12 in the orbital path around the backing roller 14.

One form of progressive movement of the machine to cause the advance is shown in F IG; 2, where the arrows I5 indicate the steps in which the movement takes place, that is to say a forward step, a rear step, a sideway movement parallel to the axis of the roller a forward step, etc.

FIGURES 3 and 4:

In FIGS. 3 and 4, the crumbling of the rock under the action of the machine is illustrated. In FIG. 3, a work roller. 12 is shown having made contact with a rock face It). The working central zone 16 of the roller traverses the rock surface by rolling it in a direction normal to that indicated by the plane of the paper. With large force applied through the backing member, a very high localized pressure is exerted on the rock, and it breaks by chipping or crumbling (FIG. 4). The arrows 22 show the direction in which the backing member supplies penetrative force.

With movement of the machine along and into the rock face, the rock breaks away in the area in which it has least sup port, as shown in FIGS. 3 and 4. Where the rock face is not cut away as shown in FIGS. 3 and 4, the rock face will crumble where the zones 16 of the rollers 12 act on it.

FIGURES 5 and 6:

The operating head of another machine is seen in FIGS. 5 and 6. The backing roller I4 is driven (by means not illustrated) in the direction of the arrow 24. The cages 20 which have apertures 25 through which the raised zones 16 of the rollers 12 project will also preferably be driven, as shown-by the arrow 26, at approximately half the speed of the backing roller 14. This ensures that the work rollers 12 roll with the minimum of scouring on the backing roller I4 and on the rock surface. The cages 20 also serve to prevent or inhibit the rock H075 (In and grit being disposed on the surface of the roller 14 where it may cause damage as the end 17 of the rollers 12 roll on it.

FIGURE 7:

Where the machine is designed to work simultaneously at several points on the rock face, means to apply force to the backing structure should be supplied. These can take the form of yokes or half-shoes 30 which bear directly on the circular backing roller 14. The arrows 32 indicate the direction in which the force is applied.

FIGURES 8 and 9:

A layout using a machine of the general design of that of FIG. 7 is shown in FIGS. 8 and 9. Here there is a rock-breaking machine which has reaction means in the form of a beam 38 which bears against the wall 36 of an excavation 34 such as a crosscut. Gulleys 42 extend into the face at suitable intervals to accommodate the hydraulic drive mechanisms 44 for the backing roller or shaft 14. Pushers or rams 40 apply force to backing roller or shaft 14 which are capable of considerable expansion. This system, as shown in FIG. 9, allows a relatively narrow band of rock indicated at 45 to be removed up to a considerable distance from the face. To permit progressive rock breaking along the face length, it is necessary that the working head of the machine should move along the face. The extent of this movement might however be confined to a few inches. After traversing the rock face, the head returns to its original starting position. Because of this requirement, and because of the necessity of gulleys such as those shown at 42, the machine is likely to be used in fairly specialized conditions.

FIGURES 10,11,12 and 13:

In FIG. a more versatile machine is shown. This machine 110 comprises a backing roller 1 14 about which a single row of small rollers 112 orbit. A pair of bushes 115 are interposed between the backing and work rollers and these carry a cage that has stepped recesses which wholly receive the ends 117 of the work rollers 112. The bushes 115 are replacable and protect the backing roller 114. The roller 114 has a raised central shoulder 113 against which the inner ends of the bushes 115 bear and which spaces the bushes 115 to provide a groove 118 in which the enlarged, circular section, central portion 116 of the rollers 112 can be accommodated. The roller 114 is mounted in bearings 119 in a very rigid structure 121 including a substantial backing member 122. Thrust washers 123 are interposed between the outer ends of the bushes 115 and the structure 121 to provide side retension for the bushes and shaft assembly.

The roller 114 is rotated by an hydraulic motor 124 also carried by the structure 121 and connectedto the roller 114 through a reduction gearing 125 and a sprocket and chain drive 126 which is arranged to give a further speed reduction. All these parts except perhaps the motor 124 will be covered and a suitable end cap 127 is provided at the end of the structure adjacent the end of the roller 114. Annular sealing rings 128 seal the projecting sides of the bushes 115. A cage 120 is also provided to minimize the ingress of dirt and grit between the rollers 112 and the bushes 115.

The cage 120, the ends of the rollers 112 and the thrust washers are not correctly shown in FIG. 10. These parts are, for clarity, illustrated in FIGS. 11 and 12 in two optional arrangements.

The outer ends 129 of the roller ends 117 are rounded and bear on correspondingly shaped thrust plates 131. (See FIGS. 11 and 12). The thrust plates 131 bear on to inwardly directed wedges 136 (FIGS. 11) or 133 (FIG. 12) of the cage 120. The flange 132 of the embodiment of FIG. 11 bears against a shoulder 134 at the side of the recess in the bush 115. In the embodiment of FIG. 12 the outer side 135 of the flange 132 is inclined and a complementarily shaped wedge 136 is interposed between the flange 132 and the side of the recess. A

screw 132a passes through the cage and engages the wedge 136 to push it against the cage and hence to eliminate clearance of the roller end 129.

In both these embodiments. a conduit 138 is provided to bring fluid, e.g., oil or water under high pressure to the rounded outer ends 129 of the rollers 112. This pressurizes the interior of the cage and also serves to minimize the ingress of dirt thereinto.

The structure 121 includes a rigid backing member 139 against which the ram or rams (not shown) can act to propel the machine head towards the rock face.

The machine is pivoted about a point so that its head may describe an arc and means for effecting this is described with reference to subsequently numbered figures. 4

Advance of the machine over an are indicated by arrow A and which has in planes parallel to the roller axes in effect peels a layer of rock from the rock face -141, as illustrated in FIG. 13.

This machine allows ample space for the lashing or clearing away of the rock broken by it, so that stoppages to clear the face are at a minimum.

FIGURES 14 AND 15:

One form of mechanism for moving the head along the face is shown in FIG. 14 and 15. Here there is a machine of the same type as that of FIG. 11. A ram 52 carries the structure 121 and is pivoted about an axis 70 between an upper and a lower frame 72 that are in turn designed to be propped in the region of the pivot 70. A hydraulic cylinder 74 is connected between a remote point on the frames 72 and a point on the ram 52. Actuation of the cylinder 74 causes the ram 52 to move in its arc (as shown by the arrows 76 in FIG. 14). A similar cylinder 78 (FIG. 15) in the ram 52 supplies the force to keep the head of the machine in high-pressure contact on the face of the rock into which it is advancing. This movement is shown by the arrow 80.

FIGURE 16:

The sophistication of the machine might be increased by supplying a second prop-type clamp 82 as shown in FIG. 16 rearward of the first prop 73 which is attached to the frame 72. Equipped with suitable control devices, the machine might be set to operate unsupervised for some time, the props 72 and 82 supporting the machine alternately as it advances continuously.

FIGURE 17:

Another arrangement for moving the head, arcuately is shown in FIG. 17. Here the head structure 121 is carried on an arm 141 which is slidable on an arcuate guide 142 formed on an elongated member 143 against which a number of rams 144 act. A long stroke jack 145 having its piston rod 146 projecting from each end with rollers 147 at each end is mounted on the member 143. A pair of cables 148 are provided. Each cable 148 has one end connected to the member and the other connected to the arm 141. Each cable 148 passes over a roller 147 and over a fixed roller 145. It will be seen that by moving the piston rod 146 of the jack 145 the cables 148 will cause the arm 141 to swing along the path determined by the guide 142.

The ends of the rams 144 are attached to a block 149 which is provided with apertures 151 therein through which clamping props (not shown) may pass to hold the block 149 in position.

FIGURES 18 and 19:

A further embodiment is shown in FIGS. 18 and 19 where the head is rotatable about the axis of a ram 80, the machine excavating a circular hole or tunnel into the face. Rock broken is forced behind the head, and with suitable supplies of water, air and the like can be removed continuously, allowing the machine to make rapid and continuous advance. Rotation of the head 121 on its ram is shown by the arrow 83.

GENERAL:

In all the embodiments of the invention, the work rollers roll on both the backing member and the rock face. There is thus not a cutting action, and scour and abrasion are reduced. The working zones of the rollers 12 will thus have a relatively long effective life, although it is naturally desirable to form or tip them with a hard, abrasion-resistant material or to provide such material, for example tungsten carbide as studs or the like embedded in the working zone of the rollers. Supplies of water to facilitate the removal of broken rock and to lay dust will, of course be provided.

By making the ends of the work rollers long compared with the raised working zone, and supporting the ends fully on the backing structure, very large localized pressures on the rock face can be accommodated in the machine.

lclaim:

1. Apparatus for breaking rock comprising backing structure; at least one small roller having ends, and being mounted for movement on the backing structure on which the said ends roll in line contact, the roller further having a raised central rock-working zone; means to drive the roller in its path relatively to the backing structure, and means to apply force to the backing structure so that the working zone of the roller may bear with a substantial localized pressure on the rock surface and cause it to break.

2. Apparatus as claimed in claim 1 wherein the central rockworking zone of the roller is of circular section.

3. Apparatus as claimed in claim 1 wherein the backing structure is mounted on a member which is capable of stepwise sideways movement.

4. Apparatus as claimed in claim 1 further comprising reaction means against which the means to apply force to the backing structure can act.

5. Apparatus as claimed in claim 1 comprising a series of small rollers mounted for movement in an endless path around the backing structure.

6. Apparatus as claimed in claim 5 further comprising reaction means against which the means to apply force to the backing structure can act, wherein the backing structure is mounted on a member which is movable relative to the reaction means so that the small rollers can move in an arc in the plane parallel to their axes.

7. Apparatus as claimed in claim 5 wherein the backing structure comprises large roller.

8. Apparatus as claimed in claim 7 wherein the backing structure also comprises bush means surrounding the large roller and on which the small rollers roll.

9. Apparatus as claimed in claim 5 further comprising a cage for the small rollers.

10. Apparatus as claimed in claim 9 wherein the cage serves to inhibit dirt coming between the rolling surfaces and the parts of the backing structures on which they roll.

11. Apparatus as claimed in claim 10 wherein the interior of the cage is supplied with liquid under pressure. 

1. Apparatus for breaking rock comprising backing structure; at least one small roller having ends, and being mounted for movement on the backing structure on which the said ends roll in line contact, the roller further having a raised central rockworking zone; means to drive the roller in its path relatively to the backing structure, and means to apply force to the backing structure so that the working zone of the roller may bear with a substantial localized pressure on the rock surface and cause it to break.
 2. Apparatus as claimed in claim 1 wherein the central rock-working zone of the roller is of circular section.
 3. Apparatus as claimed in claim 1 wherein the backing structure is mounted on a member which is capable of stepwise sideways movement.
 4. Apparatus as claimed in claim 1 further comprising reaction means against which the means to apply force to the backing structure can act.
 5. Apparatus as claimed in claim 1 comprising a series of small rollers mounted for movement in an endless path around the backing structure.
 6. Apparatus as claimed in claim 5 further comprising reaction means against which the means to apply force to the backing structure can act, wherein the backing structure is mounted on a member which is movable relative to the reaction means so that the small rollers can move in an arc in the plane parallel to their axes.
 7. Apparatus as claimed in claim 5 wherein the backing structure comprises large roller.
 8. Apparatus as claimed in claim 7 wherein the backing structure also comprises bush means surrounding the large roller and on which the small rollers roll.
 9. Apparatus as claimed in claim 5 further comprising a cage for the small rollers.
 10. Apparatus as claimed in claim 9 wherein the cage serves to inhibit dirt coming between the rolling surfaces and the parts of the backing structures on which they roll.
 11. Apparatus as claimed in claim 10 wherein the interior of the cage is supplied with liquid under pressure. 